Film-thrusting cassette

ABSTRACT

A film cassette comprises a spool rotatable in unwinding and winding directions to thrust a leader section of a film roll coiled about the spool from the cassette and to return the leader to the cassette; a pair of flanges coaxially arranged along the spool to normally permit each of the flanges to be independently rotated relative to the spool in the two directions and to radially confine the film roll within skirted peripheries of the flanges; and a film stripper received between the leader and the next-inward convolution of the film roll to free the leader from the flanges by inducing the leader to flex the flanges away from one another at their skirted peripheries responsive to rotation of the spool in the unwinding direction. According to the invention, the spool has a pair of integral disks located within the skirted peripheries of the flanges to include the film roll between the disks. At least one of the flanges can be fixed to at least one of the disks to make the fixed flange rotate in unity with the spool when the spool is rotated in the unwinding direction, to improve the ability of the spool to thrust the leader from the cassette. Conversely, the fixed flange can be released from the disk to permit it to be independently rotated relative to the spool when the spool is rotated in the winding direction, to generally ensure the leader will be rewound within the skirted periphery of the flange.

CROSS-REFERENCE TO RELATED APPLICATIONS

Reference is made to commonly assigned copending applications Ser. No.07/320,440, entitled FILM CASSETTE, and filed Mar. 8, 1989 in the nameof John J. Niedospial; Ser. No. 07/415,750, entitled FILM CASSETTE, andfiled Sept. 27, 1989 in the name of John J. Niedospial; Ser. No.07/464,048 entitled FILM CASSETTE, and filed Jan. 12, 1990 in the names,of Michael T. Wolf et al.; and Ser. No. 07/464,264 entitled FILMCASSETTE, and filed Jan. 12, 1990, in the names of C. M. McCormick etal.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates generally to the field of photography, andparticularly to a film cassette containing roll film. More specifically,the invention relates to a film cassette that is capable ofautomatically advancing a non-protruding film leader to the exterior ofthe cassette shell responsive to unwinding rotation of a film spoolwithin the shell.

2. Description of the Prior Art

In conventional 35 mm film manufacturers' cassettes, such asmanufactured by Eastman Kodak Co. and Fuji Photo Film Co. Ltd., thefilmstrip is wound on a flanged spool which is rotatably supportedwithin a cylindrical shell. A leading or forward-most section of thefilmstrip approximately 21/3 inches long, commonly referred to as a"film leader", normally protrudes from a light-trapped slit or mouth ofthe cassette shell. One end of the spool has a short axial extensionwhich projects from the shell, enabling the spool to be turned by hand.If the spool is initially rotated in an unwinding direction, the filmroll inside the shell will tend to expand radially since the inner endof the filmstrip is attached to the spool, and the fogged leader sectionprotruding from the slit will remain stationary. The film roll canexpand radially until a firm non-slipping relation is establishedbetween its outermost convolution and the inner curved wall of theshell. Once this non-slipping relation exists, there is a binding effectbetween the film roll and the shell which prevents further rotation ofthe spool in the unwinding direction. Thus, rotation of the spool in theunwinding direction cannot serve to advance the filmstrip out of theshell, and it is necessary in the typical 35 mm camera to engage theprotruding leader section to draw the filmstrip out of the shell.

A 35 mm film cassette has been proposed which, unlike conventional filmcassettes, can be operated to automatically advance a film leader out ofthe cassette shell by rotating the film spool in the unwindingdirection. The film leader originally is located entirely inside thecassette shell. Specifically, in U.S. Pat. No. 4,423,943, granted Jan.3, 1984, there is disclosed a film cassette wherein the outermostconvolution of the film roll wound on the film spool is radiallyconstrained by respective circumferential lips of two axially spacedflanges of the spool to prevent the outermost convolution fromcontacting an inner curved wall of the cassette shell. The trailing endof the filmstrip is secured to the film spool, and the forward orleading end of the filmstrip is slightly tapered purportedly to allow itto freely extend from between the circumferential lips and rest againstthe shell wall at a location inwardly of a non-lightight film passagewayto the outside of the cassette shell. During initial unwinding rotationof the film spool, the leading end of the filmstrip is advanced alongthe shell wall until it reaches an inner entrance to the filmpassageway. Then, it is advanced into and through the film passageway tothe outside of the cassette shell. The passageway has a width that isless than the width of the filmstrip, thus resulting in the filmstripbeing transversely bowed as it is uncoiled from the film spool, andthereby facilitating movement of the film edges under thecircumferential lips of the flanges. However, severe transverse bowingof the filmstrip in order to move its longitudinal edges under thecircumferential lips of the flanges may damage the filmstrip.

Like the type of film cassette disclosed in U.S. Pat. No. 4,423,923,commonly assigned U.S. Pat. Nos. 4,834,306 granted May 30, 1989, and No.4,848,693, granted July 18, 1989, each disclose a film cassette that iscapable of automatically advancing a non-protruding film leader to theoutside of the cassette shell in response to rotation of the film spoolin the unwinding direction. Specifically, there is disclosed a filmcassette wherein a film roll is wound on a spool between a pair ofcoaxially spaced, independently rotatable flanges. The two flanges haverespective circumferential annular lips which prevent the outermostconvolution of the film roll, including its leading end, fromclock-springing into contact with the interior wall of the cassetteshell. When the spool is initially rotated in the unwinding direction,the flanges may momentarily remain stationary and the film roll, sinceits inner end is secured to the spool, tends to expand radially toensure a firm non-slipping relation between the outermost convolutionand the annular lips. Once the non-slipping relation exists, continuedrotation of the spool will similarly rotate the flanges. This allowsstationary internal spreaders to deflect successive portions of theannular lips to an axial dimension exceeding the film width, in turnallowing the leading end and successive sections of the film roll to befreed from the radial confinement of the annular lips and to be advancedinto and through a lighttight film passageway to the outside of thecassette shell. A stripper-guide located adjacent an inner entrance tothe film passageway diverts the leading end of the film roll into thepassageway by being received between the leading end and the next-inwardconvolution of the film roll responsive to unwinding rotation of thespool.

THE CROSS-REFERENCED APPLICATIONS

Cross-referenced applications Ser. Nos. 07/320,440 and 07/415,750 eachdisclose a film cassette wherein a film roll whose outermost convolutionis a film leader is coiled about a spool rotatable within the cassetteshell, a pair of flexible independently rotatable flanges are coaxiallyarranged on the spool to radially confine the film leader withinrespective skirted peripheries of the flanges to prevent the leader fromsubstantially contacting an interior wall of the cassette shell, and afilm stripper-guide projecting from the interior wall is receivedbetween a leading end of the film leader and the next-inward convolutionof the film roll to free the leader from the flanges and guide theleader through a lighttight film passageway to the exterior of thecassette shell responsive to rotation of the spool in a film unwindingdirection. Specifically, the stripper-guide frees the film leader fromthe flexible flanges by inducing the leader to flex the flanges awayfrom one another at their skirted peripheries during unwinding rotationof the spool. Moreover, the film leader and at least one of the flangesinclude mutual engagement means for maintaining the leading end of theleader spaced at least a minimum radial distance from the next-inwardconvolution of the film roll sufficient to locate the leading end withinrange of the stripper-guide, to ensure that the leading end will beadvanced over the stripper-guide responsive to rotation of the spool inthe film unwinding direction.

SUMMARY OF THE INVENTION

According to the invention, it has been found that by fixing at leastone of the film confining flanges to the film spool during unwindingrotation of the spool, as contrasted with allowing each of the flangesto remain rotatable independently of the spool as in commonly assignedU.S. Pat. Nos. 4,834,306 and 4,848,693 and in cross-referencedapplications Ser. Nos. 07/320,440 and 07/415,750, there is immediatelyeffected a frictional relationship between the outermost convolution ofthe film roll and the skirted periphery of the fixed flange whichimproves the ability of the spool to thrust the film leader through thelighttight passageway to the exterior of the cassette shell. Inparticular, the frictional relationship increases the pushing force thespool will apply to the film leader to propel the leader out of thecassette shell. Moreover, it has been found that by allowing both of theflanges to be rotated independently of the spool during winding rotationof the spool, as in commonly assigned U.S. Pat. Nos. 4,834,306 and4,848,693 and in cross-referenced applications Ser. Nos. 07/320,440 and07/415,750, it is substantially ensured that the leader can be rewoundwithin the skirted peripheries of the flanges without being obstructedby the skirted peripheries.

Thus, the invention may be summarized as follows:

A film cassette comprising (a) a spool rotatable in a film unwindingdirection to thrust a leader section of a film roll coiled about thespool to the exterior of the cassette and in a film winding direction toreturn the leader to the interior of the cassette, and (b) a pair offlanges coaxially arranged along the spool to normally permit each ofthe flanges to be independently rotated relative to the spool in thefilm unwinding and film winding directions and to radially confine thefilm roll within skirted peripheries of the flanges, is characterized byincluding:

a pair of disks axially spaced along the spool in a fixed relation tothe spool, with respective outer faces of the disks located adjacentcorresponding inner faces of the flanges to position the disks withinthe skirted peripheries of the flanges to include the film roll betweenthe disks; and

securement means for securing one of the flanges in face-to-face contactto one of the disks to make the flange rotate in unity with the spoolwhen the spool is rotated in the film unwinding direction, to improvethe ability of the spool to thrust the leader from the cassette, and forreleasing the flange from the disk to permit the flange to beindependently rotated relative to the spool when the spool is rotated inthe film winding direction, to substantially ensure the leader can berewound within the skirted periphery of the flange.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view of a film cassette according to apreferred embodiment of the invention;

FIG. 2 is an elevation view of the film cassette, illustrating thecassette shell open to reveal a film roll coiled about a film spool;

FIG. 3 is an end view partly in cross-section of the cassette shell, thefilm roll and the film spool, illustrating the manner in which the filmroll is originally stored on the film spool;

FIGS. 4, 5, 6 and 7 are end views similar to FIG. 3, illustrating themanner in which the film roll is unwound from the film spool;

FIGS. 8 and 9 are elevation views of the film roll and the film spool,illustrating the manner in which the film roll is originally stored onthe film spool;

FIGS. 10 and 11 are elevation views similar to FIGS. 8 and 9,illustrating the manner in which the film roll is unwound from the filmspool; and

FIGS. 12 and 13 are elevation views, partly in section, of the film rolland the film spool, illustrating the manner in which one of a pair offilm confining flanges of the spool may be fixed to the spool forconcurrent rotation with the spool.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The invention is disclosed as being embodied preferably in a 35 mm filmcassette. Because the features of this type of film cassette aregenerally well known, the description which follows is directed inparticular to elements forming part of or cooperating directly with thedisclosed embodiment. It is to be understood, however, that otherelements not specifically shown or described may take various formsknown to persons of ordinary skill in the art.

Referring now to the drawings, FIGS. 1, 2 and 12 depict an improved 35mm film cassette 1 comprising a lighttight cassette shell 3 and a filmspool 5 which is rotatable about an axis X in film unwinding and filmwinding directions U and W within the cassette shell. The cassette shell3 consists of two shell halves 7 and 9 which are mated along respectivegrooved and stepped edge portions 11 and 13. The mated halves 7 and 9define respective upper and lower aligned circular openings 15 and 17for an outer open end 19 of a spool core or hub 21 and an outer open end22 of a securement member 23, and they define a narrowrelatively-straight film passageway 25 to the exterior of the cassetteshell 3. The securement member 23 is supported via an inner integralspindle 27, received in a coaxial bore (not shown) in the spool core 21,for rotation relative to the spool core in the film unwinding and filmwinding directions U and W and for translation telescopically inward andoutward along the spool core in opposite directions. The spool core 21has two opposite facing inclined cam slots 28 cut in its periphery whichcontain respective follower pins 29 radially projecting from thesecurement member 23, to limit rotation and translation of thesecurement member relative to the spool core. The spool core 21 and thesecurement member 23 each include an annular groove 30 which mates witha corresponding edge portion 31 of the respective openings 15 and 17 torotatably support the film spool 5 for rotation about the axis X in thefilm unwinding and film winding directions U and W. A known black velvetor plush material 32 lines the interior of the film passageway 25 toprevent ambient light from entering the film passageway.

A roll 33 of 35 mm filmstrip F is coiled about the spool core 21 betweena pair of coaxial rigid disks 34 and 35, preferably integrally formedwith the spool core, to form successive film convolutions. As shown inFIG. 3, the film roll 33 includes an outermost convolution whichcomprises a film leader 36 having a leading or forward end section 37,and it includes a next-inward convolution 39 coiled behind the outermostconvolution. The inner or trailing end section of an innermostconvolution (not shown) of the film roll 33 is secured to the spool core21. The two disks 34 and 35 cover opposite sides of the film roll 33which are defined by corresponding opposite longitudinal edges 40 and 41of each successive convolution of the film roll. See FIG. 12.

A pair of upper and lower identical, very thin, flexible film confiningflanges 42 and 43 are coaxially spaced along the spool core 21 as shownin FIGS. 1, 2, 12 and 13. The two flanges 42 and 43 comprise respectiveflat portions 45 and 47 and respective integral annular lips or skirts49 and 51 which circumferentially extend from the flat portions. The twoflat portions 45 and 47 have respective inner faces 45' and 47' whichare located adjacent corresponding outer faces 34' and 35' of the coredisks 34 and 35 to allow the annular lips 49 and 51 to circumferentiallyoverlap the peripheral edges of the core disks, and they have respectivecentral holes (not shown) through which the spool core 21 axiallyextends. The spool core 21 as shown in FIG. 12 has respectivecircumferential grooves 56 for supporting the flanges 42 and 43 in thegrooves to permit the flanges to be independently rotated relative tothe spool core in the film unwinding and film winding directions U andW. The annular lips 49 and 51 overlap the film leader (outermostconvolution) 36 of the film roll 33 radially outwardly of thelongitudinal edges 40 and 41 of the leader to radially confine theleader to thus prevent it from radially expanding or clock-springinginto substantial contact with an interior curved wall 57 of the cassetteshell 3. See FIG. 2. A lip-receiving notch 59 is cut in the film leader(outermost convolution) 36 along its longitudinal edge 41, relativelyclose to its leading end 37, to receive a peripheral section 51' of theannular lip 51. This allows a relatively short edge-section 61 of thefilm leader (outermost convolution) 36 connecting the leading end 37 andthe notch 59 to overlap the annular lip 51 radially outwardly to thusmaintain the leading end spaced a radial distance D from the next-inwardconvolution 39 of the film roll 33. See FIGS. 4 and 9. The leading end37 has a forward edge 63 inclined from the longitudinal edge 40 of thefilm leader (outermost convolution) 36 to the other longitudinal edge 41of the leader to form a forward-most tip or tab 65 of the leader which,like the edge-section 61, overlaps the annular lip 51 radiallyoutwardly. See FIGS. 1, 2, 8 and 9.

A film stripper-guide 67 projecting from the interior wall 57 of thecassette half 7 is positioned immediately inward of the inner entranceto the film passageway 25 to be received between the leading end 37 ofthe film leader (outermost convolution) 36 and the next-inwardconvolution 39, close to the forward-most tip 65 of the leader, to pickup the leading end and guide it into the film passageway responsive torotation of the spool core 21 in the unwinding direction U. See FIGS. 1,4-7, 10 and 11. The leading end 37 will be advanced over thestripper-guide 67 and into the film passageway 25, rather than betweenthe stripper-guide and the next-inward convolution 39, because it isspaced the radial distance D from the latter convolution. Thus, as shownin FIG. 4, the leading end 37 will be located within range of thestripper-guide 67 due to such spacing D from the next-inward convolution39.

When the leading end 37 of the film leader (outermost convolution) 36 isadvanced over the stripper-guide 67 responsive to rotation of the spoolcore 21 in the unwinding direction U, the longitudinal edges 40 and 41of the leader start to gently flex respective arcuate portions of thetwo flanges 42 and 43 axially away from one another, first to allow thenotch 59 to separate from the lip section 51', and then to allowsuccessive longitudinal sections of the leader to exit from between theflanges to the outside of the cassette shell 3. See FIGS. 10 and 11. Thelocal flexing of the flanges 42 and 43 occurs because the film widthW_(F) between the longitudinal film edges 40 and 41 is slightly greaterthan the axial spacing A_(S) between the annular lips 49 and 51 of theflanges. Moreover, successive convolutions of the film roll 33 have aresistance to transverse bowing that is greater than the resistance ofthe flanges 42 and 43 to be locally flexed. A pair of flat curvedbearing members 69 extend from the interior wall 57 of the cassetteshell 3 to lie flatly against successive arcuate sections of the twoflat portions 45 and 47 of the flanges 42 and 43 as the flanges arelocally flexed axially away from one another, to thereby assure returnof the flexed sections of the flanges to their normal originalnon-flexed condition. See FIGS. 1 and 2.

A film flattening member 71 projects from the interior wall 57 of thecassette half 9 in the vicinity of the inner entrance to the filmpassageway 25 and the stripper-guide 67 to support successivelongitudinal sections of the film leader 36, beginning with its leadingend 37, substantially flat as those sections are freed from the flanges42 and 43, to facilitate movement of the leading end into thepassageway. See FIGS. 6 and 7. The light-trapping plush 32 within thefilm passageway 25 is elevated along the passageway slightly beyond alongitudinal center line L of the passageway. The film flattening member71 as shown in FIG. 3 projects almost to the center line L in order tosupport successive sections of the film leader 36 substantially flat atthe center line. See FIGS. 6 and 7. Preferably, a substantially planarfilm-supporting face 73 of the flattening member 71 is spaced0.005"-0.030" short of the center line L, and extends widthwise of thefilm passageway 25 as shown in FIG. 1.

A slot 75 is cut in the film leader (outermost convolution) 36substantially proximate its leading end 37. A tooth 77 fixed to theinterior wall 57 of the cassette half 7 has a free pointed end 79 whichis positioned to be received in the slot 75 to thus engage the filmleader (outermost convolution) 35, when the spool core 21 is rotated inthe winding direction W as shown in FIG. 3, and to exit the slot to thusdisengage the leader, when the spool core is rotated in the unwindingdirection U as shown in FIG. 4. The engagement of the film leader(outermost convolution) 36 and the tooth 77 responsive to rotation ofthe spool core 21 in the winding direction W prevents the leading end 37of the leader from coming to rest between the stripper-guide 67 and thenext-inward convolution 39.

OPERATION

If the securement member 23 is initially rotated relative to the spoolcore 21 in the film unwinding direction U, for example by engaging akeying member 81 within the open end 22 of the securement member, thecam slots 28 in the spool core will cooperate with the follower pins 29of the securement member to translate the securement membertelescopically inward along the spool core to, in turn, pinch or clampthe flat portion 47 of the flange 43 between two drive lugs 82 of thesecurement member and the outer face 35' of the core disk 35. See FIGS.12 and 13. In essence, the flat portion 47 of the flange 43 and the coredisk 35 will be secured frictionally in face-to-face contact. Then,further rotation of the securement member 23 in the film unwindingdirection U will similarly rotate the spool core 21 and the flange 43 inthe same direction. See FIGS. 4-7, 10 and 11. As a result, the filmleader (outermost convolution) 36 will be advanced off the tooth 77 andits leading end 37 will be advanced over the stripper-guide 67, causingsuccessive arcuate portions of the flanges 42 and 43 to be flexedaxially away from one another as shown in FIG. 11. This first allows thenotch 59 in the film leader (outermost convolution) 36 to separate fromthe lip section 51' of the flange 43, and then it allows successivelongitudinal sections of the film leader to exit from between thatflange and the flange 42 to the outside of the cassette shell 3. Sincethe stripper-guide 67 initially picks up the leading end 37 of the filmleader 36 close to its forward-most tip 65, the forward edge 63 of theleading end might initially be supported along a narrow ridge 85 formingone end of the interior wall 57 of the cassette half 7. However, theleading end 37 will tend to back away from the ridge 85 and move againstthe film-supporting face 73 of the flattening member 71 as shown in FIG.6.

If the securement member 23 is rotated relative to the spool core 21 inthe film winding direction W, for example by engaging its keying member81, after some length of the filmstrip F has been advanced from thecassette shell 3, the cam slots 28 will cooperate with the follower pins29 to translate the securement member telescopically outward along thespool core to, in turn, release or unclamp the flat portion 47 of theflange 43 by separating the two drive lugs 82 from the flat portion, tothereafter permit the flange to be rotated independently of the spoolcore. Then, further rotation of the securement member 23 in the filmwinding direction W will similarly rotate the spool core 21 in the samedirection to rewind the filmstrip F onto the spool core. The spool core21 is rotated in the film winding direction W substantially until theslot 75 in the film leader (outermost convolution) 36 receives the freeend 79 of the tooth 77 to thereby re-engage the film leader to thetooth.

According to the invention, it has been found that by securing theflange 43 frictionally in face-to-face contact to the core disk 35during unwinding rotation of the spool core 21, as contrasted withallowing that flange to remain rotatable independently of the spool coreas in commonly assigned U.S. Pat. Nos. 4,834,306 and 4,848,693, there isimmediately effected a frictional relationship between the film leader(outermost convolution) 36 and the skirted periphery 51 of the flangewhich improves the ability of the film spool to thrust the film leaderthrough the lighttight passageway 25 to the exterior of the cassetteshell 3. In particular, the frictional relationship increases thepushing force the spool core 21 will apply to the film leader 36 topropel the leader out of the cassette shell 3. Moreover, it has beenfound that by allowing both of the flanges 42 and 43 to be rotatedindependently of the spool core 21 during winding rotation of the filmspool 5, as in commonly assigned U.S. Pat. Nos. 4,4834,306 and No.4,848,693, it is substantially ensured that the leader can be rewoundwithin the skirted peripheries 49 and 51 of the flanges without beingobstructed by the skirted peripheries.

When the flange 43 is secured frictionally in face-to-face contact tothe core disk 35, it might be possible that the flange could be forciblyrotated relative to the spool core 21 [in the film unwinding directionU]. For this reason, there is provided a pair of aligned radial slots 87cut in the flange 43 for receiving the respective drive lugs 82 of thesecurement member 23, to affirmatively couple the flange and thesecurement member, responsive to rotation of the securement memberrelative to the flange in the film unwinding direction U. In essence,the cooperation of the cam slots 28 and the follower pins 29 totranslate the securement member 23 telescopically inward along the spoolcore 21 to, in turn, clamp the flange 43 between the drive lugs 82 andthe core disk 35 will serve to move the drive lugs into the radial slots87 of the flange. Conversely, when the securement member 23 is firstrotated relative to the spool core 21 in the film winding direction W,the cooperation of the cam slots 28 and the follower pins 29 totranslate the securement member telescopically outward along the spoolcore will, in turn, move the drive lugs out of the radial slots 87 touncouple the securement member from the flange 43. Preferably, therespective end faces of the drive lugs 82 are suitably inclined tofacilitate their movement out of the radial slots 87 without tearing theflange 43.

The invention has been described with reference to a preferredembodiment. However, it will be appreciated that variations andmodifications can be effected within the ordinary skill in the artwithout departing from the scope of the invention.

We claim:
 1. A film cassette comprising (a) a spool rotatable in a filmunwinding direction to thrust a leader section of a film roll coiledabout said spool to the exterior of said cassette and in a film windingdirection to return said leader to the interior of the cassette, and (b)a pair of flanges coaxially arranged along said spool to normally permiteach of said flanges to be independently rotated relative to the spoolin the film unwinding and film winding directions and to radiallyconfine said film roll within skirted peripheries of the flanges, ischaracterized by including:a pair of disks axially spaced along saidspool in a fixed relation to the spool, with respective outer faces ofsaid disks located adjacent corresponding inner faces of said flanges toposition the disks within said skirted peripheries of the flanges toinclude said film roll between said disks; and securement means forsecuring one of said flanges in face-to-face contact to one of saiddisks to make the flange rotate in unity with said spool when the spoolis rotated in the film unwinding direction, to improve the ability ofthe spool to thrust said leader from said cassette, and for releasingthe flange from the disk to permit the flange to be independentlyrotated relative to said spool when the spool is rotated in the filmwinding direction, to substantially ensure said leader can be rewoundwithin said skirted periphery of the flange.
 2. A film cassette asrecited in claim 1, wherein said securement means includes a securementmember movable relative to said spool for clamping one of said flangesto one of said disks to secure the flange frictionally in face-to-facecontact to the disk and for unclamping the flange from the disk torelease the flange from the disk.
 3. A film cassette as recited in claim1, wherein one of said flanges may be shifted axially against one ofsaid disks to secure the flange in face-to-face contact to the disk, andsaid securement member is movable relative to said spool in respectiveopposite directions to clamp one of said flanges axially against one ofsaid disks and to unclamp the flange from the disk.
 4. A film cassetteas recited in claim 1, wherein one of said flanges may be shiftedaxially against one of said disks to secure the flange in face-to-facecontact to the disk, said securement member is coaxially arranged withrespect to said spool for rotation relative to the spool in the filmunwinding and film winding directions and for translation along thespool, and said spool and said securement member have cooperatingcamming elements for translating the securement member in oppositedirections along the spool to clamp one of said flanges axially againstone of said disks responsive to rotation of the securement memberrelative to the spool in the film unwinding direction and to unclamp theflange from the disk responsive to rotation of the securement memberrelative to the spool in the film winding direction.
 5. A film cassetteas recited in claim 4, wherein said securement member includes drivemeans for affirmatively coupling with one of said flanges to rotate theflange in the film unwinding direction should the flange be forciblyrotated relative to the securement member in that direction when theflange is clamped axially against one of said disks and for uncouplingfrom the flange responsive to rotation of the securement member relativeto the flange in the film winding direction to permit the flange to beindependently rotated in that direction when the flange is unclampedfrom the disk.